The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

A 140-year-old castle with underground caves hidden in San Francisco.

A giant Troll lurks under one of Seattle's oldest bridges.

A bizarre house filled with an astounding array of collections.

High on a hill overlooking Los Angeles lives a world famous, high power conical Tesla Coil.

The legendary building that needed ghostly approval before being built.

A collection of oddities including Dr. Kevorkian's suicide device, the Thanatron.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

Try not to get slimed in Tribeca.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

Dramatic river bend surrounds a natural red-rocked pedestal.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

An emerald-green grotto just a short trip from Austin.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.